The invention relates generally to a latch needle for a knitting machine, and more particularly to the knitting needle to be assembled from an extended needle body and a latch respectively plastically formed from a synthetic resin.
There have been proposed and actually used various latch needles for knitting, but it is generally common to all of them that the needle comprises an extended needle body consisting of a shank portion, a hook portion formed at one end thereof and a butt portion at the other end, as well as a latch pivotably mounted in a slot formed in said shank portion at the root of said hook so as to angularly move by an angle of about 165.degree.-170.degree. alternately between a hook open position and a hook closed position.
In order to solve various problems or troubles caused by such alternate angular movement of the latch, for instance in order to lessen damage to the free end of the latch which is often called the latch spoon and to the side walls defining the slot, some proposals have been made as seen in e.g. U.S. Pat. Nos. 4,294,086 and 4,512,164. In order to assure that the latch will not come to rest beside or underneath the needle head when closing the hook, which is inevitably caused from the lateral mobility of the latch, U.S. Pat. No. 4,498,315 has proposed a countermeasure.
The invention does not lie in the improvements of such nature but intends ready assembly of the latch needle and consequently provide inexpensive latch needles.
In the past the latch needles have been made of a metallic material such as stainless steel, but recently such knitting needles have been made of synthetic resin. A thermoplastic resin of high mechanical strength and some flexibility, among which polyacetal, seems to be most preferable also in view of the moderate cost are marketed. The inventor has not found any printed material to be named here as to such a latch needle.
The latch having a pair of transversely protruded pivots arranged at the root portion thereof is plastically formed from said synthetic resin. Separately therefrom the extended needle body having the slot defined by a pair of cheek walls, each having a hole for engaging with said pivot is plastically formed from the synthetic resin. The width of the latch is slightly smaller than that of said the slot, but the latch integrally formed with oppositely protruded pivots cannot be brought in engagement with said holes formed in the side walls. In assembly the slot width must be spreaded with using a wedge tool and when the latch pivots are fitted in the holes, the tool is withdrawn so that opposite cheek walls are brought into the initial positions owing to the flexibility of the material. Such manual assembly is, however, not so easy particularly when the needle is of fine gauge and thus the slot width is thin.